1 files changed, 52 insertions, 0 deletions
diff --git a/editor.c b/editor.c
new file mode 100644
index 0000000000..d8340031d2
--- /dev/null
+++ b/editor.c
@@ -0,0 +1,52 @@
+#include "cache.h"
+#include "strbuf.h"
+#include "run-command.h"
+
+#ifndef DEFAULT_EDITOR
+#define DEFAULT_EDITOR "vi"
+#endif
+
+const char *git_editor(void)
+{
+	const char *editor = getenv("GIT_EDITOR");
+	const char *terminal = getenv("TERM");
+	int terminal_is_dumb = !terminal || !strcmp(terminal, "dumb");
+
+	if (!editor && editor_program)
+		editor = editor_program;
+	if (!editor && !terminal_is_dumb)
+		editor = getenv("VISUAL");
+	if (!editor)
+		editor = getenv("EDITOR");
+
+	if (!editor && terminal_is_dumb)
+		return NULL;
+
+	if (!editor)
+		editor = DEFAULT_EDITOR;
+
+	return editor;
+}
+
+int launch_editor(const char *path, struct strbuf *buffer, const char *const *env)
+{
+	const char *editor = git_editor();
+
+	if (!editor)
+		return error("Terminal is dumb, but EDITOR unset");
+
+	if (strcmp(editor, ":")) {
+		const char *args[] = { editor, path, NULL };
+
+		if (run_command_v_opt_cd_env(args, RUN_USING_SHELL, NULL, env))
+			return error("There was a problem with the editor '%s'.",
+					editor);
+	}
+
+	if (!buffer)
+		return 0;
+	if (strbuf_read_file(buffer, path, 0) < 0)
+		return error("could not read file '%s': %s",
+				path, strerror(errno));
+	return 0;
+}